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1

Fabrication and Physical Properties of SiC-GaAs Nano-Composites

100%

Kalisz G., Grzanka E., Wasik D., Świderska-Środa A., Gierlotka S., Borysiuk J., Kamińska M., Twardowski A., Pałosz B.

Acta Physica Polonica A

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2005

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vol. 108

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issue 4

717-721

EN

Nano-composites consisting of primary phase of hard nanocrystalline SiC matrix and the secondary nanocrystalline semiconductor (GaAs) phase were obtained by high-pressure zone infiltration. The synthesis process occurs in three stages: (i) at room temperature the nanopowder of SiC is compacted along with GaAs under high pressure up to 8 GPa, (ii) the temperature is increased above the melting point of GaAs up to 1600~K and, the pores are being filled with liquid, (iii) upon cooling GaAs nanocrystallites grow in the pores. Synthesis of nano-composites was performed using a toroid-type high-pressure apparatus (IHPP of the Polish Academy of Sciences, Warsaw) and six-anvil cubic press (MAX-80 at HASYLAB, Hamburg). X-ray diffraction studies were performed using a laboratory D5000 Siemens diffractometer. Phase composition, grain size, and macrostrains present in the synthesized materials were examined. Microstructure of the composites was characterized using scanning electron microscopy and high resolution transmission electron microscopy. Far-infrared reflectivity measurements were used to determine built-in strain.

2

Pressure Investigation of Tunneling in an InAlAs-InGaAs Double Barrier Structure

80%

Cury L., Dmowski L., Celeste A., Portal J., Davies M., Heath M., Sivco D., Cho A.

Acta Physica Polonica A

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1991

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vol. 79

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issue 2-3

199-202

EN

AnIn_{0.52}Al_{0.48}As-In_{0.53}Ga_{0.47}As double-barrier structure was studied under hydrostatic pressures up to 15 kbar. Two resonances in the I(V) curves are observed. The possible tunneling mechanisms to interpret this effect are analysed.

3

Earth Materials at High Pressure and Temperature: Recent Contributions from in situ Synchrotron X-Ray Diffraction

80%

Redfern S. A. T.

Acta Physica Polonica A

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1997

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vol. 91

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issue 4

659-668

EN

The application of synchrotron X-ray powder diffraction to the study of minerals and understanding of the structure and dynamics of the Earth's deep interior is summarised. The salient features of the diamond anvil cell and large-volume multi-anvil cell high-P/T apparatus as used at synchrotron radiation sources are described, and recent developments and applications of these techniques within high-P/T mineralogy are reviewed.

4

^{57}Fe Hyperfine Interactions in the Sc(Fe_{1-x}Ni_x)_2 Laves Phases Synthesized under High Pressure

80%

Wiertel M., Surowiec Z., Budzyński M., Tsvyashchenko A.

Acta Physica Polonica A

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2008

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vol. 114

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issue 6

1517-1527

EN

The structural and microscopic magnetic properties of the pseudobinary Sc(Fe_{1-x}Ni_x)_2 system prepared under high pressure of 8 GPa were studied by X-ray diffraction and Mössbauer measurements in the range of 0.0 ≤ x ≤ 0.60. The samples for 0.0 ≤ x ≤ 0.10 have the hexagonal C14-type structure and those for 0.30 ≤ x ≤ 0.60 crystallize in the C15-type structure. Both the magnetic hyperfine field on ^{57}Fe and the Curie temperature decrease with the increasing Ni content and the system becomes paramagnetic for x ≈ 0.60 at room temperature. The form and temperature dependences of the Mössbauer spectra for 0.40 ≤ x ≤ 0.50 indicate the coexistence of paramagnetic and ferromagnetic regions in the samples and occurrence of magnetic clusters with a wide distribution of the Curie temperatures. It is interesting that T_C for the compounds obtained under high pressure are by about 100 K smaller in comparison with those for the isostructural samples produced under normal pressure even though interatomic distances are practically equal in the both types of compounds.

5

Influence of Pressure on the Magnetic Response of the Low-Dimensional Quantum Magnet Cu(H₂O)₂(C₂H₈N₂)SO₄

80%

Peprah M., VanGennep D., Blasiola B., Quintero P., Tarasenko R., Xia J., Hamlin J., Meisel M., Orendáčová A.

Acta Physica Polonica A

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2017

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vol. 131

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issue 4

901-903

EN

The influence of pressure on the low-dimensional molecular magnet Cu(H₂O)₂(en)SO₄ (en = ethylenediamine = C₂H₈N₂) has theoretically been shown to affect the exchange interactions of the material. Herein, the results of an experimental study of hydrostatic pressure effects on the temperature dependence of the magnetization are reported. Using two different pressure cells, the magnetization measurements were performed between 2 K and 9.6 K with pressures ranging from ambient to 5.0 GPa. The data preliminarily suggest the presence of a shift in the magnetization peak of the material at the lowest temperatures and at the highest applied pressures. These data serve as a guide for future experimental work employing pressure to study this intriguing system.

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Fabrication and Physical Properties of SiC-GaAs Nano-Composites

Pressure Investigation of Tunneling in an InAlAs-InGaAs Double Barrier Structure

Earth Materials at High Pressure and Temperature: Recent Contributions from in situ Synchrotron X-Ray Diffraction

^{57}Fe Hyperfine Interactions in the Sc(Fe_{1-x}Ni_x)_2 Laves Phases Synthesized under High Pressure

Influence of Pressure on the Magnetic Response of the Low-Dimensional Quantum Magnet Cu(H₂O)₂(C₂H₈N₂)SO₄